Rows of wave 'farms' up to 1,000km long facing the Atlantic could generate around 11% of the UK’s current power generation. Photograph: Richard Cooke/Alamy

The Atlantic ocean off Cornwall and the west coast of Scotland show the greatest promise for generating electricity from the waves that crash around the British Isles, according to new research.

The regions came top in a report which maps, for the first time, the sites around the UK with the most potential for wave power. Some of the highest waves, in the Rockall Trough to the west of Scotland, measure up to 29m from crest to trough.

Rows of wave "farms" up to 1,000km long facing the Atlantic could generate around 11% of the UK's current power generation, the Carbon Trust analysis suggests. While the theoretical resource is as high as 18GW, around 10GW of capacity is more realistic given practical and economic constraints, it said.

Stephen Wyatt, the report's author, said: "The promise is huge. The UK has become the world's proving ground for wave and tidal energy. The potential home market for wave power while significant is even greater abroad. The International Energy Agency have estimated a global market of up to 200GW of marine power by 2050. If the UK were to capture some 15% of this the benefits for the UK economy have been evaluated at £4bn."

While the technology to harness the renewable source of energy is still at an early stage, it is hoped a test bed off Orkney and a wave "hub" off Cornwall will bring it to commercial scale. "We don't yet have commercial devices that have been built and tested at the scale needed to operate in such hostile and remote environments. But we may not be waiting for too long," said Wyatt.

The Scottish government, in particular, has talked up the economic and environmental promise of wave power, with first minister Alex Salmond saying last year that the machines will in the next few years move to "substantial commercial development". In August, Scotland launched a £10m competition for wave- and tidal-powered devices. MPs in February said the UK could become a leader exporter of such technology if given significant government backing.

The Carbon Trust examined the UK's Exclusive Economic Zone to see which areas had the most energy potential, at the lowest cost. It concluded the best sites could generate electricity at a cost of 20-25.3p/kWh, compared to around 5.5-11p/kWh for gas power and 8-11p/kWh for onshore wind today.

The ideal sites were those that offered the best balance between how close they were to shore, water depth and raw wave energy. Wyatt told the Guardian: "It was surprising that the best sites were so far offshore – our analysis indicates that it is worth going so far offshore to harness the more energetic waves."